A row of Google self-driving Lexus cars at a Google event in Mountain View, California, last year.
Photograph: Eric Risberg/AP

As a handful of Google’s self-driving cars venture outside California for the first time, arriving on the streets of Austin, Texas, this week, the company has revealed its plans to build many more fully autonomous prototypes, and possibly move towards mass manufacturing.

When Google introduced the low-speed, two-seater electric cars last year, it said it was going to build just 100 vehicles by the end of 2015. But speaking at the California Public Utilities Commission on Thursday, Sarah Hunter, head of policy for GoogleX, said: “We’re … making a few hundred of them. We’re making them to enable our team to learn how to actually build a self-driving vehicle from the ground up.”

Last month, the Guardian revealed that Google had set up its own car company, Google Auto, to manufacture the completely driverless cars without steering wheels, brake or accelerator pedals. While Google says it has no plans to market these prototypes, and has previously talked about partnerships with established car companies, Hunter admitted that it is now considering making and selling self-driving cars itself.

“A model where we manufacture cars for sale will require the same sort of electric vehicle charging that exists today,” she told an audience of regulators and politicians. “Our prototype vehicles are fully electric. That’s not to say the eventual vehicle we mass manufacture won’t be a hybrid.”

All the cars built so far have been assembled on the outskirts of Detroit by Google’s manufacturing partner, the engineering firm Roush. Any move into mass manufacturing would require a much larger facility and is probably years off.

Hunter also shared new details about how the existing driverless prototypes work. “All [the car] has is a ‘go’ button, a ‘please slow down and stop’ button and a ‘stop pretty quickly’ button,” she said. “The intention is that the passenger gets in the vehicle, says into microphone, take me to Safeway, and the car does the entire journey.”

Google’s self-driving cars currently require highly detailed maps of the areas they’re operating in, with centimetre accuracy of road features like lanes, roundabouts and traffic lights. They are also limited to 25mph so that Google could get them on to public roads without expensive and time-consuming crash tests. Even more importantly, they need safety drivers able to take control back in an instant if the system malfunctions. California is slowly working on regulations that will pave the way for the operation of completely driverless vehicles by the public.

All of this means that Google is unlikely to move its self-driving technology into full production any time soon. “We haven’t decided yet how we’re going to bring this to market,” admitted Hunter. “Right now, our engineers are trying to figure out … how to make a car genuinely drive itself. Once we figure that out, we’ll figure out how to bring it to market and in which way. Is it something that we manufacture at scale for sale to individuals? Or is it something that we own and operate as a service?”

That model would pit Google as a direct competitor to Uber, the ride-sharing service that is developing its own self-driving cars. Uber’s policy director, Ashwini Chhabra, also spoke at the California Public Utilities Commission yesterday, saying: “We have a shared goal which is getting people out from behind the wheel of single occupancy vehicles and into safer, more efficient modes of transit.”

Uber CEO Travis Kalanick believes that autonomous taxis will eventually reduce the cost of journeys to well below that of owning a car. Chhabra thinks this would enable traffic-busting carpool vehicles, dramatically improve road safety, and reduce emissions. “If global demand keeps steady, we’ll have 3.4bn cars on the planet by 2050,” he said. “That’s clearly not sustainable. That’s part of why we’re thinking about how to stop carmageddon, which of all the -geddons is one of the scarier ones.”

Chhabra ventured that fully autonomous vehicles might be roaming American roads as soon as 2035. The head of an advanced transportation research programme at Berkeley disagreed, suggesting 2075 was more realistic. When the asked the same question, Sarah Hunter of GoogleX merely quipped: “Whenever California passes its operational regulations. We’re just waiting for that.”